Adds a notice to vendors about the SHOW_CUSTOM_BOOTSCREEN directive

Marlin/example_configurations/Cartesio/Configuration.h

 // build by the user have been successfully uploaded into firmware.
 #define STRING_CONFIG_H_AUTHOR "(MaukCC, CartesioE)" // Who made the changes.
 #define SHOW_BOOTSCREEN
-#define STRING_SPLASH_LINE1 "Cartesio" // will be shown during bootup in line1
-#define STRING_SPLASH_LINE2 "Marlin " SHORT_BUILD_VERSION // will be shown during bootup in line 2
+#define STRING_SPLASH_LINE1 SHORT_BUILD_VERSION // will be shown during boot in line 1
+#define STRING_SPLASH_LINE2 WEBSITE_URL         // will be shown during boot in line 2
+
+//
+// *** VENDORS PLEASE READ *****************************************************
+//
+// Marlin now allow you to have a vendor boot image to be displayed on machine
+// start. When SHOW_CUSTOM_BOOTSCREEN is defined Marlin will first show your
+// custom boot image and them the default Marlin boot image is shown.
+//
+// We suggest for you to take advantage of this new feature and keep the Marlin
+// boot image unmodified. For an example have a look at the bq Hephestos 2
+// example configuration folder.
+//
+//#define SHOW_CUSTOM_BOOTSCREEN
+#if ENABLED(SHOW_BOOTSCREEN) && ENABLED(SHOW_CUSTOM_BOOTSCREEN)
+  #include "_bootscreen.h"
+#endif
 
 // @section machine
 

Marlin/example_configurations/Felix/Configuration.h

 // build by the user have been successfully uploaded into firmware.
 #define STRING_CONFIG_H_AUTHOR "(none, default config)" // Who made the changes.
 #define SHOW_BOOTSCREEN
-#define STRING_SPLASH_LINE1 SHORT_BUILD_VERSION // will be shown during bootup in line 1
-#define STRING_SPLASH_LINE2 WEBSITE_URL         // will be shown during bootup in line 2
+#define STRING_SPLASH_LINE1 SHORT_BUILD_VERSION // will be shown during boot in line 1
+#define STRING_SPLASH_LINE2 WEBSITE_URL         // will be shown during boot in line 2
+
+//
+// *** VENDORS PLEASE READ *****************************************************
+//
+// Marlin now allow you to have a vendor boot image to be displayed on machine
+// start. When SHOW_CUSTOM_BOOTSCREEN is defined Marlin will first show your
+// custom boot image and them the default Marlin boot image is shown.
+//
+// We suggest for you to take advantage of this new feature and keep the Marlin
+// boot image unmodified. For an example have a look at the bq Hephestos 2
+// example configuration folder.
+//
+//#define SHOW_CUSTOM_BOOTSCREEN
+#if ENABLED(SHOW_BOOTSCREEN) && ENABLED(SHOW_CUSTOM_BOOTSCREEN)
+  #include "_bootscreen.h"
+#endif
 
 // @section machine
 

Marlin/example_configurations/Felix/DUAL/Configuration.h

 // build by the user have been successfully uploaded into firmware.
 #define STRING_CONFIG_H_AUTHOR "(none, default config)" // Who made the changes.
 #define SHOW_BOOTSCREEN
-#define STRING_SPLASH_LINE1 SHORT_BUILD_VERSION // will be shown during bootup in line 1
-#define STRING_SPLASH_LINE2 WEBSITE_URL         // will be shown during bootup in line 2
+#define STRING_SPLASH_LINE1 SHORT_BUILD_VERSION // will be shown during boot in line 1
+#define STRING_SPLASH_LINE2 WEBSITE_URL         // will be shown during boot in line 2
+
+//
+// *** VENDORS PLEASE READ *****************************************************
+//
+// Marlin now allow you to have a vendor boot image to be displayed on machine
+// start. When SHOW_CUSTOM_BOOTSCREEN is defined Marlin will first show your
+// custom boot image and them the default Marlin boot image is shown.
+//
+// We suggest for you to take advantage of this new feature and keep the Marlin
+// boot image unmodified. For an example have a look at the bq Hephestos 2
+// example configuration folder.
+//
+//#define SHOW_CUSTOM_BOOTSCREEN
+#if ENABLED(SHOW_BOOTSCREEN) && ENABLED(SHOW_CUSTOM_BOOTSCREEN)
+  #include "_bootscreen.h"
+#endif
 
 // @section machine
 

Marlin/example_configurations/Hephestos/Configuration.h

 // build by the user have been successfully uploaded into firmware.
 #define STRING_CONFIG_H_AUTHOR "(none, default config)" // Who made the changes.
 #define SHOW_BOOTSCREEN
-#define STRING_SPLASH_LINE1 SHORT_BUILD_VERSION // will be shown during bootup in line 1
-#define STRING_SPLASH_LINE2 WEBSITE_URL         // will be shown during bootup in line 2
+#define STRING_SPLASH_LINE1 SHORT_BUILD_VERSION // will be shown during boot in line 1
+#define STRING_SPLASH_LINE2 WEBSITE_URL         // will be shown during boot in line 2
+
+//
+// *** VENDORS PLEASE READ *****************************************************
+//
+// Marlin now allow you to have a vendor boot image to be displayed on machine
+// start. When SHOW_CUSTOM_BOOTSCREEN is defined Marlin will first show your
+// custom boot image and them the default Marlin boot image is shown.
+//
+// We suggest for you to take advantage of this new feature and keep the Marlin
+// boot image unmodified. For an example have a look at the bq Hephestos 2
+// example configuration folder.
+//
+//#define SHOW_CUSTOM_BOOTSCREEN
+#if ENABLED(SHOW_BOOTSCREEN) && ENABLED(SHOW_CUSTOM_BOOTSCREEN)
+  #include "_bootscreen.h"
+#endif
 
 // @section machine
 

Marlin/example_configurations/Hephestos_2/Configuration.h

 // build by the user have been successfully uploaded into firmware.
 #define STRING_CONFIG_H_AUTHOR "@jbrazio" // Who made the changes.
 #define SHOW_BOOTSCREEN
-#define STRING_SPLASH_LINE1 SHORT_BUILD_VERSION // will be shown during bootup in line 1
-#define STRING_SPLASH_LINE2 WEBSITE_URL         // will be shown during bootup in line 2
+#define STRING_SPLASH_LINE1 SHORT_BUILD_VERSION // will be shown during boot in line 1
+#define STRING_SPLASH_LINE2 WEBSITE_URL         // will be shown during boot in line 2
+
+//
+// *** VENDORS PLEASE READ *****************************************************
+//
+// Marlin now allow you to have a vendor boot image to be displayed on machine
+// start. When SHOW_CUSTOM_BOOTSCREEN is defined Marlin will first show your
+// custom boot image and them the default Marlin boot image is shown.
+//
+// We suggest for you to take advantage of this new feature and keep the Marlin
+// boot image unmodified. For an example have a look at the bq Hephestos 2
+// example configuration folder.
+//
+//#define SHOW_CUSTOM_BOOTSCREEN
+#if ENABLED(SHOW_BOOTSCREEN) && ENABLED(SHOW_CUSTOM_BOOTSCREEN)
+  #include "_bootscreen.h"
+#endif
 
 // @section machine
 

Marlin/example_configurations/K8200/Configuration.h

 // build by the user have been successfully uploaded into firmware.
 #define STRING_CONFIG_H_AUTHOR "(K8200, @CONSULitAS)" // Who made the changes.
 #define SHOW_BOOTSCREEN
-#define STRING_SPLASH_LINE1 SHORT_BUILD_VERSION // will be shown during bootup in line 1
-#define STRING_SPLASH_LINE2 WEBSITE_URL         // will be shown during bootup in line 2
+#define STRING_SPLASH_LINE1 SHORT_BUILD_VERSION // will be shown during boot in line 1
+#define STRING_SPLASH_LINE2 WEBSITE_URL         // will be shown during boot in line 2
+
+//
+// *** VENDORS PLEASE READ *****************************************************
+//
+// Marlin now allow you to have a vendor boot image to be displayed on machine
+// start. When SHOW_CUSTOM_BOOTSCREEN is defined Marlin will first show your
+// custom boot image and them the default Marlin boot image is shown.
+//
+// We suggest for you to take advantage of this new feature and keep the Marlin
+// boot image unmodified. For an example have a look at the bq Hephestos 2
+// example configuration folder.
+//
+//#define SHOW_CUSTOM_BOOTSCREEN
+#if ENABLED(SHOW_BOOTSCREEN) && ENABLED(SHOW_CUSTOM_BOOTSCREEN)
+  #include "_bootscreen.h"
+#endif
 
 // @section machine
 

Marlin/example_configurations/K8400/Configuration.h

 // build by the user have been successfully uploaded into firmware.
 #define STRING_CONFIG_H_AUTHOR "(Anthony Birkett, default config)" // Who made the changes.
 #define SHOW_BOOTSCREEN
-#define STRING_SPLASH_LINE1 SHORT_BUILD_VERSION // will be shown during bootup in line 1
-#define STRING_SPLASH_LINE2 WEBSITE_URL         // will be shown during bootup in line 2
+#define STRING_SPLASH_LINE1 SHORT_BUILD_VERSION // will be shown during boot in line 1
+#define STRING_SPLASH_LINE2 WEBSITE_URL         // will be shown during boot in line 2
+
+//
+// *** VENDORS PLEASE READ *****************************************************
+//
+// Marlin now allow you to have a vendor boot image to be displayed on machine
+// start. When SHOW_CUSTOM_BOOTSCREEN is defined Marlin will first show your
+// custom boot image and them the default Marlin boot image is shown.
+//
+// We suggest for you to take advantage of this new feature and keep the Marlin
+// boot image unmodified. For an example have a look at the bq Hephestos 2
+// example configuration folder.
+//
+//#define SHOW_CUSTOM_BOOTSCREEN
+#if ENABLED(SHOW_BOOTSCREEN) && ENABLED(SHOW_CUSTOM_BOOTSCREEN)
+  #include "_bootscreen.h"
+#endif
 
 // @section machine
 

Marlin/example_configurations/K8400/Dual-head/Configuration.h

 // build by the user have been successfully uploaded into firmware.
 #define STRING_CONFIG_H_AUTHOR "(Anthony Birkett, default config)" // Who made the changes.
 #define SHOW_BOOTSCREEN
-#define STRING_SPLASH_LINE1 SHORT_BUILD_VERSION // will be shown during bootup in line 1
-#define STRING_SPLASH_LINE2 WEBSITE_URL         // will be shown during bootup in line 2
+#define STRING_SPLASH_LINE1 SHORT_BUILD_VERSION // will be shown during boot in line 1
+#define STRING_SPLASH_LINE2 WEBSITE_URL         // will be shown during boot in line 2
+
+//
+// *** VENDORS PLEASE READ *****************************************************
+//
+// Marlin now allow you to have a vendor boot image to be displayed on machine
+// start. When SHOW_CUSTOM_BOOTSCREEN is defined Marlin will first show your
+// custom boot image and them the default Marlin boot image is shown.
+//
+// We suggest for you to take advantage of this new feature and keep the Marlin
+// boot image unmodified. For an example have a look at the bq Hephestos 2
+// example configuration folder.
+//
+//#define SHOW_CUSTOM_BOOTSCREEN
+#if ENABLED(SHOW_BOOTSCREEN) && ENABLED(SHOW_CUSTOM_BOOTSCREEN)
+  #include "_bootscreen.h"
+#endif
 
 // @section machine
 

Marlin/example_configurations/RepRapWorld/Megatronics/Configuration.h

 // build by the user have been successfully uploaded into firmware.
 #define STRING_CONFIG_H_AUTHOR "RepRapWorld.com" // Who made the changes.
 #define SHOW_BOOTSCREEN
-#define STRING_SPLASH_LINE1 SHORT_BUILD_VERSION // will be shown during bootup in line 1
-#define STRING_SPLASH_LINE2 WEBSITE_URL         // will be shown during bootup in line 2
+#define STRING_SPLASH_LINE1 SHORT_BUILD_VERSION // will be shown during boot in line 1
+#define STRING_SPLASH_LINE2 WEBSITE_URL         // will be shown during boot in line 2
+
+//
+// *** VENDORS PLEASE READ *****************************************************
+//
+// Marlin now allow you to have a vendor boot image to be displayed on machine
+// start. When SHOW_CUSTOM_BOOTSCREEN is defined Marlin will first show your
+// custom boot image and them the default Marlin boot image is shown.
+//
+// We suggest for you to take advantage of this new feature and keep the Marlin
+// boot image unmodified. For an example have a look at the bq Hephestos 2
+// example configuration folder.
+//
+//#define SHOW_CUSTOM_BOOTSCREEN
+#if ENABLED(SHOW_BOOTSCREEN) && ENABLED(SHOW_CUSTOM_BOOTSCREEN)
+  #include "_bootscreen.h"
+#endif
 
 // @section machine
 

Marlin/example_configurations/RigidBot/Configuration.h

 // build by the user have been successfully uploaded into firmware.
 #define STRING_CONFIG_H_AUTHOR "(none, default config)" // Who made the changes.
 #define SHOW_BOOTSCREEN
-#define STRING_SPLASH_LINE1 SHORT_BUILD_VERSION // will be shown during bootup in line 1
-#define STRING_SPLASH_LINE2 WEBSITE_URL         // will be shown during bootup in line 2
+#define STRING_SPLASH_LINE1 SHORT_BUILD_VERSION // will be shown during boot in line 1
+#define STRING_SPLASH_LINE2 WEBSITE_URL         // will be shown during boot in line 2
+
+//
+// *** VENDORS PLEASE READ *****************************************************
+//
+// Marlin now allow you to have a vendor boot image to be displayed on machine
+// start. When SHOW_CUSTOM_BOOTSCREEN is defined Marlin will first show your
+// custom boot image and them the default Marlin boot image is shown.
+//
+// We suggest for you to take advantage of this new feature and keep the Marlin
+// boot image unmodified. For an example have a look at the bq Hephestos 2
+// example configuration folder.
+//
+//#define SHOW_CUSTOM_BOOTSCREEN
+#if ENABLED(SHOW_BOOTSCREEN) && ENABLED(SHOW_CUSTOM_BOOTSCREEN)
+  #include "_bootscreen.h"
+#endif
 
 // @section machine
 

Marlin/example_configurations/SCARA/Configuration.h

 // build by the user have been successfully uploaded into firmware.
 #define STRING_CONFIG_H_AUTHOR "(none, default config)" // Who made the changes.
 #define SHOW_BOOTSCREEN
-#define STRING_SPLASH_LINE1 SHORT_BUILD_VERSION // will be shown during bootup in line 1
-#define STRING_SPLASH_LINE2 WEBSITE_URL         // will be shown during bootup in line 2
+#define STRING_SPLASH_LINE1 SHORT_BUILD_VERSION // will be shown during boot in line 1
+#define STRING_SPLASH_LINE2 WEBSITE_URL         // will be shown during boot in line 2
+
+//
+// *** VENDORS PLEASE READ *****************************************************
+//
+// Marlin now allow you to have a vendor boot image to be displayed on machine
+// start. When SHOW_CUSTOM_BOOTSCREEN is defined Marlin will first show your
+// custom boot image and them the default Marlin boot image is shown.
+//
+// We suggest for you to take advantage of this new feature and keep the Marlin
+// boot image unmodified. For an example have a look at the bq Hephestos 2
+// example configuration folder.
+//
+//#define SHOW_CUSTOM_BOOTSCREEN
+#if ENABLED(SHOW_BOOTSCREEN) && ENABLED(SHOW_CUSTOM_BOOTSCREEN)
+  #include "_bootscreen.h"
+#endif
 
 // @section machine
 

Marlin/example_configurations/TAZ4/Configuration.h

 // build by the user have been successfully uploaded into firmware.
 #define STRING_CONFIG_H_AUTHOR "(Aleph Objects, Inc, TAZ  config)" // Who made the changes.
 #define SHOW_BOOTSCREEN
-#define STRING_SPLASH_LINE1 SHORT_BUILD_VERSION // will be shown during bootup in line 1
-#define STRING_SPLASH_LINE2 WEBSITE_URL         // will be shown during bootup in line 2
+#define STRING_SPLASH_LINE1 SHORT_BUILD_VERSION // will be shown during boot in line 1
+#define STRING_SPLASH_LINE2 WEBSITE_URL         // will be shown during boot in line 2
+
+//
+// *** VENDORS PLEASE READ *****************************************************
+//
+// Marlin now allow you to have a vendor boot image to be displayed on machine
+// start. When SHOW_CUSTOM_BOOTSCREEN is defined Marlin will first show your
+// custom boot image and them the default Marlin boot image is shown.
+//
+// We suggest for you to take advantage of this new feature and keep the Marlin
+// boot image unmodified. For an example have a look at the bq Hephestos 2
+// example configuration folder.
+//
+//#define SHOW_CUSTOM_BOOTSCREEN
+#if ENABLED(SHOW_BOOTSCREEN) && ENABLED(SHOW_CUSTOM_BOOTSCREEN)
+  #include "_bootscreen.h"
+#endif
 
 // @section machine
 

Marlin/example_configurations/WITBOX/Configuration.h

 // build by the user have been successfully uploaded into firmware.
 #define STRING_CONFIG_H_AUTHOR "(bq Witbox)" // Who made the changes.
 #define SHOW_BOOTSCREEN
-#define STRING_SPLASH_LINE1 SHORT_BUILD_VERSION // will be shown during bootup in line 1
-#define STRING_SPLASH_LINE2 WEBSITE_URL         // will be shown during bootup in line 2
+#define STRING_SPLASH_LINE1 SHORT_BUILD_VERSION // will be shown during boot in line 1
+#define STRING_SPLASH_LINE2 WEBSITE_URL         // will be shown during boot in line 2
+
+//
+// *** VENDORS PLEASE READ *****************************************************
+//
+// Marlin now allow you to have a vendor boot image to be displayed on machine
+// start. When SHOW_CUSTOM_BOOTSCREEN is defined Marlin will first show your
+// custom boot image and them the default Marlin boot image is shown.
+//
+// We suggest for you to take advantage of this new feature and keep the Marlin
+// boot image unmodified. For an example have a look at the bq Hephestos 2
+// example configuration folder.
+//
+//#define SHOW_CUSTOM_BOOTSCREEN
+#if ENABLED(SHOW_BOOTSCREEN) && ENABLED(SHOW_CUSTOM_BOOTSCREEN)
+  #include "_Bootscreen.h"
+#endif
 
 // @section machine
 

Marlin/example_configurations/adafruit/ST7565/Configuration.h

 // build by the user have been successfully uploaded into firmware.
 #define STRING_CONFIG_H_AUTHOR "(none, default config)" // Who made the changes.
 #define SHOW_BOOTSCREEN
-#define STRING_SPLASH_LINE1 SHORT_BUILD_VERSION // will be shown during bootup in line 1
-#define STRING_SPLASH_LINE2 WEBSITE_URL         // will be shown during bootup in line 2
+#define STRING_SPLASH_LINE1 SHORT_BUILD_VERSION // will be shown during boot in line 1
+#define STRING_SPLASH_LINE2 WEBSITE_URL         // will be shown during boot in line 2
+
+//
+// *** VENDORS PLEASE READ *****************************************************
+//
+// Marlin now allow you to have a vendor boot image to be displayed on machine
+// start. When SHOW_CUSTOM_BOOTSCREEN is defined Marlin will first show your
+// custom boot image and them the default Marlin boot image is shown.
+//
+// We suggest for you to take advantage of this new feature and keep the Marlin
+// boot image unmodified. For an example have a look at the bq Hephestos 2
+// example configuration folder.
+//
+//#define SHOW_CUSTOM_BOOTSCREEN
+#if ENABLED(SHOW_BOOTSCREEN) && ENABLED(SHOW_CUSTOM_BOOTSCREEN)
+  #include "_bootscreen.h"
+#endif
 
 // @section machine
 

Marlin/example_configurations/delta/biv2.5/Configuration.h

 // build by the user have been successfully uploaded into firmware.
 #define STRING_CONFIG_H_AUTHOR "(none, default config)" // Who made the changes.
 #define SHOW_BOOTSCREEN
-#define STRING_SPLASH_LINE1 SHORT_BUILD_VERSION // will be shown during bootup in line 1
-#define STRING_SPLASH_LINE2 WEBSITE_URL         // will be shown during bootup in line 2
+#define STRING_SPLASH_LINE1 SHORT_BUILD_VERSION // will be shown during boot in line 1
+#define STRING_SPLASH_LINE2 WEBSITE_URL         // will be shown during boot in line 2
+
+//
+// *** VENDORS PLEASE READ *****************************************************
+//
+// Marlin now allow you to have a vendor boot image to be displayed on machine
+// start. When SHOW_CUSTOM_BOOTSCREEN is defined Marlin will first show your
+// custom boot image and them the default Marlin boot image is shown.
+//
+// We suggest for you to take advantage of this new feature and keep the Marlin
+// boot image unmodified. For an example have a look at the bq Hephestos 2
+// example configuration folder.
+//
+//#define SHOW_CUSTOM_BOOTSCREEN
+#if ENABLED(SHOW_BOOTSCREEN) && ENABLED(SHOW_CUSTOM_BOOTSCREEN)
+  #include "_bootscreen.h"
+#endif
 
 // @section machine
 

Marlin/example_configurations/delta/generic/Configuration.h

 // build by the user have been successfully uploaded into firmware.
 #define STRING_CONFIG_H_AUTHOR "(none, default config)" // Who made the changes.
 #define SHOW_BOOTSCREEN
-#define STRING_SPLASH_LINE1 SHORT_BUILD_VERSION // will be shown during bootup in line 1
-#define STRING_SPLASH_LINE2 WEBSITE_URL         // will be shown during bootup in line 2
+#define STRING_SPLASH_LINE1 SHORT_BUILD_VERSION // will be shown during boot in line 1
+#define STRING_SPLASH_LINE2 WEBSITE_URL         // will be shown during boot in line 2
+
+//
+// *** VENDORS PLEASE READ *****************************************************
+//
+// Marlin now allow you to have a vendor boot image to be displayed on machine
+// start. When SHOW_CUSTOM_BOOTSCREEN is defined Marlin will first show your
+// custom boot image and them the default Marlin boot image is shown.
+//
+// We suggest for you to take advantage of this new feature and keep the Marlin
+// boot image unmodified. For an example have a look at the bq Hephestos 2
+// example configuration folder.
+//
+//#define SHOW_CUSTOM_BOOTSCREEN
+#if ENABLED(SHOW_BOOTSCREEN) && ENABLED(SHOW_CUSTOM_BOOTSCREEN)
+  #include "_bootscreen.h"
+#endif
 
 // @section machine
 

Marlin/example_configurations/delta/kossel_mini/Configuration.h

 // build by the user have been successfully uploaded into firmware.
 #define STRING_CONFIG_H_AUTHOR "(none, default config)" // Who made the changes.
 #define SHOW_BOOTSCREEN
-#define STRING_SPLASH_LINE1 SHORT_BUILD_VERSION // will be shown during bootup in line 1
-#define STRING_SPLASH_LINE2 WEBSITE_URL         // will be shown during bootup in line 2
+#define STRING_SPLASH_LINE1 SHORT_BUILD_VERSION // will be shown during boot in line 1
+#define STRING_SPLASH_LINE2 WEBSITE_URL         // will be shown during boot in line 2
+
+//
+// *** VENDORS PLEASE READ *****************************************************
+//
+// Marlin now allow you to have a vendor boot image to be displayed on machine
+// start. When SHOW_CUSTOM_BOOTSCREEN is defined Marlin will first show your
+// custom boot image and them the default Marlin boot image is shown.
+//
+// We suggest for you to take advantage of this new feature and keep the Marlin
+// boot image unmodified. For an example have a look at the bq Hephestos 2
+// example configuration folder.
+//
+//#define SHOW_CUSTOM_BOOTSCREEN
+#if ENABLED(SHOW_BOOTSCREEN) && ENABLED(SHOW_CUSTOM_BOOTSCREEN)
+  #include "_bootscreen.h"
+#endif
 
 // @section machine
 

Marlin/example_configurations/delta/kossel_pro/Configuration.h

 // build by the user have been successfully uploaded into firmware.
 #define STRING_CONFIG_H_AUTHOR "(none, default config)" // Who made the changes.
 #define SHOW_BOOTSCREEN
-#define STRING_SPLASH_LINE1 SHORT_BUILD_VERSION // will be shown during bootup in line 1
-#define STRING_SPLASH_LINE2 WEBSITE_URL         // will be shown during bootup in line 2
+#define STRING_SPLASH_LINE1 SHORT_BUILD_VERSION // will be shown during boot in line 1
+#define STRING_SPLASH_LINE2 WEBSITE_URL         // will be shown during boot in line 2
+
+//
+// *** VENDORS PLEASE READ *****************************************************
+//
+// Marlin now allow you to have a vendor boot image to be displayed on machine
+// start. When SHOW_CUSTOM_BOOTSCREEN is defined Marlin will first show your
+// custom boot image and them the default Marlin boot image is shown.
+//
+// We suggest for you to take advantage of this new feature and keep the Marlin
+// boot image unmodified. For an example have a look at the bq Hephestos 2
+// example configuration folder.
+//
+//#define SHOW_CUSTOM_BOOTSCREEN
+#if ENABLED(SHOW_BOOTSCREEN) && ENABLED(SHOW_CUSTOM_BOOTSCREEN)
+  #include "_bootscreen.h"
+#endif
 
 // @section machine
 

Marlin/example_configurations/delta/kossel_xl/Configuration.h

 // build by the user have been successfully uploaded into firmware.
 #define STRING_CONFIG_H_AUTHOR "(oxivanisher)" // Who made the changes.
 #define SHOW_BOOTSCREEN
-#define STRING_SPLASH_LINE1 SHORT_BUILD_VERSION // will be shown during bootup in line 1
-#define STRING_SPLASH_LINE2 WEBSITE_URL         // will be shown during bootup in line 2
+#define STRING_SPLASH_LINE1 SHORT_BUILD_VERSION // will be shown during boot in line 1
+#define STRING_SPLASH_LINE2 WEBSITE_URL         // will be shown during boot in line 2
+
+//
+// *** VENDORS PLEASE READ *****************************************************
+//
+// Marlin now allow you to have a vendor boot image to be displayed on machine
+// start. When SHOW_CUSTOM_BOOTSCREEN is defined Marlin will first show your
+// custom boot image and them the default Marlin boot image is shown.
+//
+// We suggest for you to take advantage of this new feature and keep the Marlin
+// boot image unmodified. For an example have a look at the bq Hephestos 2
+// example configuration folder.
+//
+//#define SHOW_CUSTOM_BOOTSCREEN
+#if ENABLED(SHOW_BOOTSCREEN) && ENABLED(SHOW_CUSTOM_BOOTSCREEN)
+  #include "_bootscreen.h"
+#endif
 
 // @section machine
 

Marlin/example_configurations/makibox/Configuration.h

 // build by the user have been successfully uploaded into firmware.
 #define STRING_CONFIG_H_AUTHOR "(none, default config)" // Who made the changes.
 #define SHOW_BOOTSCREEN
-#define STRING_SPLASH_LINE1 SHORT_BUILD_VERSION // will be shown during bootup in line 1
-#define STRING_SPLASH_LINE2 WEBSITE_URL         // will be shown during bootup in line 2
+#define STRING_SPLASH_LINE1 SHORT_BUILD_VERSION // will be shown during boot in line 1
+#define STRING_SPLASH_LINE2 WEBSITE_URL         // will be shown during boot in line 2
+
+//
+// *** VENDORS PLEASE READ *****************************************************
+//
+// Marlin now allow you to have a vendor boot image to be displayed on machine
+// start. When SHOW_CUSTOM_BOOTSCREEN is defined Marlin will first show your
+// custom boot image and them the default Marlin boot image is shown.
+//
+// We suggest for you to take advantage of this new feature and keep the Marlin
+// boot image unmodified. For an example have a look at the bq Hephestos 2
+// example configuration folder.
+//
+//#define SHOW_CUSTOM_BOOTSCREEN
+#if ENABLED(SHOW_BOOTSCREEN) && ENABLED(SHOW_CUSTOM_BOOTSCREEN)
+  #include "_bootscreen.h"
+#endif
 
 // @section machine
 

Marlin/example_configurations/tvrrug/Round2/Configuration.h

 // build by the user have been successfully uploaded into firmware.
 #define STRING_CONFIG_H_AUTHOR "(none, default config)" // Who made the changes.
 #define SHOW_BOOTSCREEN
-#define STRING_SPLASH_LINE1 SHORT_BUILD_VERSION // will be shown during bootup in line 1
-#define STRING_SPLASH_LINE2 WEBSITE_URL         // will be shown during bootup in line 2
+#define STRING_SPLASH_LINE1 SHORT_BUILD_VERSION // will be shown during boot in line 1
+#define STRING_SPLASH_LINE2 WEBSITE_URL         // will be shown during boot in line 2
+
+//
+// *** VENDORS PLEASE READ *****************************************************
+//
+// Marlin now allow you to have a vendor boot image to be displayed on machine
+// start. When SHOW_CUSTOM_BOOTSCREEN is defined Marlin will first show your
+// custom boot image and them the default Marlin boot image is shown.
+//
+// We suggest for you to take advantage of this new feature and keep the Marlin
+// boot image unmodified. For an example have a look at the bq Hephestos 2
+// example configuration folder.
+//
+//#define SHOW_CUSTOM_BOOTSCREEN
+#if ENABLED(SHOW_BOOTSCREEN) && ENABLED(SHOW_CUSTOM_BOOTSCREEN)
+  #include "_Bootscreen.h"
+#endif
 
 // @section machine